1. Field of the Technology
The present disclosure relates generally to methods and apparatus for use in a system acquisition scan, and more particularly to system acquisition utilizing a pilot signal of a non-requested system as a timing reference for remaining channels.
2. Description of the Related Art
Wireless communication systems are widely deployed to provide various types of communication such as voice and data. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), or some other modulation techniques. A Wideband (W-CDMA) system provides certain advantages over other types of systems, including increased system capacity. Wireless communication systems typically include a plurality of base stations. Base stations in a system may communicate on one or more frequencies, and neighboring systems often utilize different frequencies as well. Systems such as W-CDMA differentiate base stations with unique codes.
Periodically, a mobile station needs to “acquire” a system, such as upon power-up or when traveling near the edge of an already acquired system. System acquisition begins with locating one or more frequencies used by a system. Subsequently, the code and its phase must be identified in order to communicate with any particular base station.
Various searching techniques are known in the art for acquiring base stations at a given frequency. System acquisition time is a function of the time required to locate the frequency of a system as well as the time required to search and acquire the code of a base station on that system. It is desirable for a mobile station to acquire base stations as rapidly as possible. Upon initial acquisition, users appreciate quick response time, so the acquisition time should be minimized. Furthermore, prompt acquisition of neighbor base stations allows the mobile station to communicate with the optimal set of base stations available. A mobile station communicating with the best set of base stations minimizes required transmit power for a given communication performance level, which results in system resources being allocated efficiently. This results in maximization of system capacity, as well as power reduction in the mobile station.
Reduced power in the mobile station translates to extended communication and standby times for a given battery configuration, or reduced battery requirements (size, weight and cost), or both. Minimizing system acquisition time facilitates realizing these benefits.
Accordingly, there is a need for reducing the time required in system acquisition scan.